Turbochargers are utilized with engines to increase the power output to weight ratio of the engine. However, engines may not need maximum boost from a turbocharger during certain operating conditions. For example, maximum boost may not be desirable when the engine is operating at knock limited conditions. Therefore, an amount of boost provided by a turbocharger may be adjusted based on engine operating conditions. One way of limiting turbocharger boost is via a wastegate. By adjusting a position of a wastegate, a portion of exhaust energy may bypass the turbocharger so that boost is limited.
However, during some operating conditions, it may be difficult to activate the wastegate so that boost can be limited. For example, at lower boost pressures and exhaust pressures there may not be enough pressure to overcome a wastegate biasing spring. Consequently, substantially all the exhaust energy is directed to the turbocharger. Thus, turbocharger operation may not be limited as may be desirable due to various design constraints of the turbocharger, bypass conduit, and the valve configuration. And, when a turbocharger is operated during cold operating conditions, components may degrade at a higher rate than is desired since exhaust energy may rotate components when lubricants may not be as effective as is desired. Therefore, it may be desirable to limit boosting during certain operating conditions, such as during cold starts. Compressor bypass valves have also been developed for use in conjunction with wastegates to substantially limit turbocharger operation during certain operating conditions, such during start-up.
The Inventors herein have found some disadvantages related to incorporating both a wastegate and a bypass valve into a turbocharger. For example, the design, manufacturing, and repair cost of the turbocharger may be increased when both a wastegate and a bypass valve are incorporated into a turbocharger system. Moreover, the likelihood of component degradation may be increased when the turbocharger's complexity is increased.
As such, various example systems and approaches are described herein. In one example, an exhaust valve comprising a first plate is configured to obstruct a first portion of a turbine bypass conduit and a first portion of a turbine inlet conduit is provided. The exhaust valve is further comprised of a second plate configured to obstruct a second portion of the turbine bypass conduit and the turbine inlet conduit. The turbine bypass conduit is substantially blocked when the first plate and the second plate are positioned together in a first plane. The exhaust valve further includes an actuation assembly configured to independently adjust the first and second plates.
In this way, operation of the turbocharger may be substantially inhibited during certain operating conditions and turbocharger operation may be throttled during other operating conditions. Thus, an engine's efficiency may be increased over a wide range of engine operating conditions by the valve.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.